This article was written by Shweta Sah, an AIDS Calgary Awareness Association volunteer blog writer. Shweta is a 2nd year M.Sc. Medicine student in the University of Calgary.
1. What is HIV drug resistance?
HIV Drug resistance is the decrease in efficiency of antiviral drug to prevent HIV replication inside the human body. In layman’s term, it is the ability of HIV to replicate in the body despite the presence of an antiviral drug which ultimately leads to failure in curing a condition or a disease.
2. How does HIV drug resistance occur?
Drug resistance happens when the drug fails to eliminate or inhibit a retrovirus that survives, reproduces and mutates itself thereby becoming resistant to the drug. This is primarily due to mutation in the HIV’s genome where RNA contains proteins and enzymes needed by the retrovirus to infect the cells and produce new virus. The new virus that contains error prone proteins (one that does not correct any mistakes while copying) then replicates at an extremely rapid rate. It ultimately takes over the defense mechanism of the host resulting in increased drug resistance. Multidrug resistance happens when the organism becomes resistant to multiple drugs at the same time.
3. Why is HIV so prone to drug resistance?
Emerging mutations of viral genome and changing treatment are the two primary reasons for HIV – prone drug resistance. In the case of emerging mutations, due to the high error-prone HIV replication; viral mutation is very rapid. Thus, a new mutated viral copy is made. More resistant the virus, higher the chances of anti-retroviral drug failure. On the other hand, changing treatments is required due to the fact that the current treatment no longer works for the host due to the mutated viral strain. The person then needs an alternative treatment which is better and more effective than the previous one.
4. What does it mean when drug resistance occurs while someone is on treatment?
Treatments are aimed at keeping the virus low, preferably undetectable and to prevent any mutation from happening. However, drug resistance while on treatment can still occur due to various reasons like improper absorption and distribution of drug into the blood stream; improper metabolization inside the body to target the virus; and finally improper removal/clearance of the drug and metabolites from the body. This can result in trough levels that are very low which leads to HIV mutations and accumulation of drug-resistance mutations at a faster rate.
Another point to consider is that drug efficacy varies from individual to individual. Factors such as body weight, height, age and gender can also contribute to this difference.
5. How can you avoid drug resistance?
Evading drug resistance is difficult, but most effective HIV suppression can be accomplished by the following regime:
1. Follow the treatment/therapy closely best suited to your body: Take precautions not to skip the doses. Skipping doses leads to HIV replication resulting in more viral load in the host. HIV-positive person must be more than 95% adherent with his/her regimen (i.e. he can only miss one dose per month even if it happens accidentally) for the drug to be effective and working.
2. Schedule medications:
Take medications at the same time to get your body accustomed to it. Scheduling it at a regular time lowers the viral reproduction rate, thereby reducing the chance of drug resistance.
3. Follow the prescribed dietary intake: Take your doctor’s advice on the dietary restrictions that apply to you while taking the prescribed medicines or combination drugs. Important thing is to stick to it and follow it on a daily basis. Adding some exercise along with the proper dietary intake can help in staying fit as some medications can make you obese.
References:
1. http://en.wikipedia.org/wiki/Drug_resistance
2. http://www.prn.org/index.php/management/article/hiv_drug_resistance_mechanisms_277
3. http://www.hivworkshop.com/drug_resistance.htm
4. http://www.thewellproject.org/en_US/Treatment_and_Trials/Things_to_Consider/Resistance.jsp
5. http://www.thebody.com/content/art14570.html
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